Naturally Occurring Radioactive Material, NORM, results primarily as a by-product of mining or petroleum production activities. In the oil field NORM is the result of material that has been extracted from the producing zone and deposited in the surface equipment in the form of solids, pipe scale, tank or pit bottoms, and sediment. The radioactive material is usually radium 226 and 228, thorium and uranium, but could also be from any other radioactive agent.
For many years this material was treated as common pipe scale and sediment. In the mid 1980's it was discovered that some of this scale was radioactive. This discovery has lead to regulations on the storage and disposal of the NORM.
Since destruction of radioactive material is not possible, it is a common practice to transport the material to a radioactive waste facility. Due to the radioactive nature of the material, landfill procedures such as disclosed in U.S. Pat. No. 4,235,562 for surface mining, U.S. Pat. No. 4,668,124 for vanadium, and U.S. Pat. No. 4,705,429 for asbestos, are undesirable from legal and environmental points of view. U.S. Pat. No. 3,108,439 discloses disposal of radioactive liquids or slurries into a subterranean formation. U.S. Pat. No. 3,513,100 discloses a method for disposing high level, solid radioactive waste by delivering such material in a continuous, water-phase cement to a subterranean formation. In U.S. Pat. No. 3,459,003 waste spent shale is formed into an aqueous slurry and pumped into a mined out area. U.S. Pat. No. 4,886,393 discloses the mixing of finely divided wastes with waste sludge to form granules or flakes which are dried for free flow into a salt cavern for disposal. U.S. Pat. No. 4,942,929 discloses the disposing of drilling fluids and drill cuttings generated during the drilling of oil and gas wells.
These methods are frequently not economical, require a special disposal site and may present environmental problems. Another problem is that the radioactive material produced as a by-product of petroleum production activities is frequently in the form of the sulfate salt. The sulfates, like those of barium and calcium which are in the same periodic group, are virtually insoluble in aqueous solutions. Thus, separation procedures which attempt to dissolve the radioactive materials, are likely to be unsuccessful.
Thus, despite the health hazard which exists from these radioactive materials, there still remains a need for an economical, safe method for treating and disposing of the by-product material from the petroleum production activities which preferably does not require the use of special disposal sites but returns the radioactive material to the place from which it came.
The presence of oxidizable materials (such as polymers, sulfides, bacteria, biomass) in bottom sediments of production and refinery storage facilities and vessels complicates the disposability of these bottom sediments. These materials themselves may be toxic and further tend to agglomerate the total sediments. There is a need in the industry to treat these sediments to render them disposable.